Flat and low dispersion in highly nonlinear slot waveguides.

We propose highly nonlinear slot waveguides with flat and low dispersion over a wide wavelength range. Si nano-crystal and chalcogenide glass are considered as slot materials. Over a 244-nm bandwidth, dispersion of 0+/-0.16 ps/(nmxm) is achieved in a silicon nano-crystal slot waveguide, with a nonlinear coefficient of 2874 /(Wm). The As(2)S(3) slot waveguide exhibits dispersion of 0+/-0.17 ps/(nmxm) over a bandwidth of 249 nm, with a nonlinear coefficient 16 times larger than that of As(2)S(3) rib waveguides and a nonlinear figure of merit three times larger than that of Si strip waveguides.